1. Field of the Art
The present invention relates generally to an electrically powered linear actuator and more particularly to an electrically powered actuator adapted for a variety of robotic or other applications. The invention has particular application to the control of robotic, pedestal or fixture welding guns and specifically, welding guns such as those utilized in the automotive industry, to the injection molding field or other applications requiring a short stroke, to the actuation of clamping fixtures and the like in various industries such as the automotive industry and to the linear movement of various apparatus requiring highly accurate positioning, among others.
2. The Prior Art
Various industries, and particularly the manufacturing industry, among others, have utilized linear actuators to control the movements of automated welding guns, automated clamping fixtures, and the like. Specifically, in the automotive industry and various other industries, actuation and control of welding guns and clamping fixtures and controlled linear movement of other fixtures and devices have been accomplished using fluid actuators such as pneumatic or hydraulic actuators. While fluid actuators have functioned reasonably well for these purposes, they inherently embody various limitations. One, because of the possibility of leaks and failure of seals, etc., there is always the concern of contamination of the worksite by a leaking fluid. Second, fluid actuators necessarily require a source of pressurized fluid and thus a fluid supply system. This leads to significant maintenance and other costs. Third, limitations sometimes exist with respect to the accuracy and positioning of linear movement and the adjustability of such movement.
Accordingly, there is a need in the art for an improved actuator which overcomes the deficiencies and limitations of the prior art, and in particular, an improved actuator which is designed for use in controlling the movement of, and accommodating the loads associated with, welding guns, clamping fixtures, injection molding fixtures, and various other fixtures and devices. A need also exists for an improved actuator which is particularly useful for applications requiring a relatively short linear stroke actuation and highly accurate positioning.